Antiaterogenicidad in vitro de extractos del alga marina Halimeda incrassata: actividad antioxidante y estudios de migración en células de la musculatura lisa / In vitro antiatherogenicity of extracts from Halimeda incrassata seaweed: antioxidant activity and smooth muscle cell migration studies

Objetivos: El objetivo de este trabajo fue evaluar el potencial ateroprotector in vitro del alga Halimeda incrassata en la migración de células de músculo liso de ratón y la oxidación de lipoproteínas en relación con su actividad antioxidante. Material y métodos: La actividad antioxidante fue determinada mediante los métodos de inhibición de radicales DPPH y la Capacidad antioxidante total (ORAC). La actividad inhibitoria de la oxidación de LDL mediada por iones Cu2+ se determinó por la cuantificación de TBARS y dienos conjugados. El efecto del extracto acuoso sobre la migración de las células de músculo liso se evaluó en la línea de células de músculo liso aórtica de ratón MOVAS-1. Resultados: Se demostró el efecto inhibidor del extracto sobre la oxidación de LDL mediada por Cu2+. El extracto del alga causa inhibición dosis-dependiente de la formación de TBARS (IC50 = 0,8 mg/mL) y dienos conjugados. Las algas tuvieron una alta actividad antioxidante en los ensayos realizados y podría estar relacionada con el contenido de compuestos fenólicos. Conclusiones: Los resultados de este trabajo representan un paso más en la caracterización de la acción ateroprotectora de Halimeda incrassata y evidencian sus posibles aplicaciones como nutracéutico y/o fitofármaco (AU)

Aim: The aim of this work was to evaluate the in vitro atheroprotective potential of the seaweed Halimeda incrassata in smooth muscle cell migration and lipoprotein oxidation in relation to its antioxidant activity. Material and methods: Antioxidant activity was determinate by DPPH• radical scavenging assay and ORAC method. The inhibitory effect of the aqueous extract on LDL oxidation mediated by Cu2+ ions was determinate by TBARS and conjugated diene quantification. The effect of the seaweed aqueous extract on smooth muscle cell migration was evaluated in MOVAS-1 mouse aortic smooth muscle cell. Results: The inhibitory effect of the aqueous extract on lipoprotein oxidation mediated by Cu2+ was demonstrated. Seaweed extract caused dose-dependent inhibition of TBARS (IC50 = 0.8 mg/mL) and conjugated dienes formation. The seaweed had a high antioxidant activity in the assays performed. The activity could be related to the phenolic content of Halimeda incrassata. Conclusions: In summary, the results of this study represent a further step in the characterization of the atheroprotective action of Halimeda incrassata and indicate the seaweed could be used for a nutraceutical and/or phytoterapeutic application (AU)

Evaluaciones toxicológicas de un extracto acuoso del alga marina Bryothamnion triquetrum (Gmelin) M. A. Howe en estudios in vitro y modelos animales / Toxicological assessments of aqueous extracts from seaweeds Bryothamnion triquetrum (Gmelin) M. A. Howe in vitro and models animal studies

Objetivo: El objetivo de este trabajo fue evaluar la toxicidad de un extracto acuoso del alga marina Bryothamnion triquetrum. Métodos: El ensayo de Ames se desarrolló con las cepas de S. typhimurium TA 1535, TA 1537 y TA 1538 con y sin activación metabólica. El estudio de citotoxicidad se realizó con células intestinales Caco-2 durante 24 y 48 horas de exposición al extracto y la viabilidad fue evaluada con la técnica de yoduro de propidio. El Estudio de Toxicidad Aguda se realizó con ratones Balc/c machos por vía oral e intraperitoneal y el Ensayo de Toxicidad por Dosis Repetidas se desarrolló con ratas Wistar de ambos sexos, durante 3 meses por vía oral con dosis de 8 y 32 mg/kg. Resultados: En el estudio de citotoxicidad con células Caco-2 se obtuvieron CL50 de 9,3 y 4,5 mg/mL con exposiciones de 24 y 48 horas respectivamente. El ensayo de Ames evidencia que no es mutágeno directo ni promutágeno hasta 1000 microg. La DL50 del extracto por vía intraperitoneal fue de 1205 mg/kg y por vía oral no se observó mortalidad en dosis de 2000 mg/kg. En el estudio de Toxicidad por Dosis Repetidas no se observó toxicidad. Conclusiones: A partir de estos resultados se puede postular que el extracto acuoso del alga marina B. triquetrum es inocuo, consideración necesaria, entre otras, para su posible uso como nutracéutico y/o fitofármaco(AU)

Aim: The aim of this work was to evaluate the toxicity of an aqueous extract from seaweed Bryothamnion triquetrum. Materials and Methods: Ames assay was developed with S. typhimurium TA 1535, TA 1537 and TA 1538 with and without metabolic activation. Citotoxicity study was carried out with intestinal cells Caco-2 during 24 and 48 hours of exhibition to the extract and the viability was evaluated with the technique of Propidium iodide. Acute Toxicity was carried out with mice Balc/c males for via oral and intraperitoneal and the Toxicity for Repeated Dose was developed with rats Wistar of both sexes, during 3 months for via oral with dose of 8 and 32 mg/kg. Results: Results of Ames assays showed that this extract is not direct mutagen or promutagen in quantity until 1000 microg. The cytotoxic effect (LC50) of Caco-2 cells after 24 and 48 h of exposition were 9,3 and 4,5 mg/mL respectively. The LD50 of the extract, with intraperitoneal administration was 1205 mg/kg and by oral via not produce mortality in doses until 2000 mg/kg. At the doses of 8 and 32 mg/kg of extract, the repeated oral administration produced no toxic effects. Conclusions: In summary, this paper adds convincing evidences in support of innocuous of the aqueous extract of B.triquetrum. Altogether; these results represent another step towards the use of this natural product as phytotherapeutical agent(AU)

Incorporation of dietary trans monounsaturated fatty acids into tissues of Walker 256 tumor-bearing rats.

The correlation between dietary trans fatty acids and neoplasia was examined in the present study. Walker 256 tumor-bearing and control rats were fed a trans monounsaturated fatty acid (MUFA)-rich diet for 8 weeks and the incorporation of trans fatty acids by tumor tissue was examined. Also, the effect of tumor growth on trans fatty acid composition of plasma and liver, and the content of thiobarbituric acid-reactive substances (TBARS) was determined. Walker 256 tumor cells presented both trans and cis MUFAs given in the diet. The equivalent diet proportions were 0.66 for trans and 1.14 for cis. Taking into consideration the proportion of trans MUFAs in plasma (11.47%), the tumor incorporated these fatty acids in a more efficient manner (18.27%) than the liver (9.34%). Therefore, the dietary trans fatty acids present in the diet are actively incorporated by the tumor. Tumor growth itself caused marked changes in the proportion of polyunsaturated fatty acids in the plasma and liver but provoked only slight modifications in both trans and cis MUFAs. Tumor growth also reduced the unsaturation index in both plasma and liver, from 97.79 to 86.83 and from 77.51 to 69.64, respectively. This effect was partially related to an increase in the occurrence of the lipid oxidation/peroxidation process of TBARS content which was increased in both plasma (from 0.428 to 0.505) and liver (from 9.425 to 127.792) due to tumor growth.

NADPH-oxidase activity and lipid peroxidation in neutrophils from rats fed fat-rich diets.

In order to investigate the effect of fat-rich diets on neutrophil functions, 21 day-aged rats were fed for 6 weeks with a control diet consisting of a regular laboratory rodent chow (4 per cent final fat content), a control diet supplied with soybean oil (15 per cent final fat content), or a control diet supplied with coconut oil (15 per cent final fat content). Glycogen-elicited peritoneal neutrophils from rats fed soybean and coconut oil-enriched diets presented a reduction in spontaneous and PMA-stimulated H2O2 generation relative to neutrophils from rats fed the control diet. The activity of superoxide dismutase, glutathione peroxidase and catalase did not change in animals fed fat-rich diets. In addition, the capacity to generate O2-, spontaneously or in response to PMA, did not change in neutrophils from animals fed fat-rich diets. Values attained matched those observed in animals fed the control diet, regardless of the method used to measure O2-, the superoxide dismutase-inhibitable reduction of cytochrome c or the lucigenin-dependent chemiluminescence. However, the initial rate of O2- generation both in resting neutrophils and in PMA-stimulated cells was significantly reduced when animals were fed with coconut or soybean oil-enriched diets due, at least in part, to a reduction in the activity of glucose-6-phosphate dehydrogenase. The concentration of thiobarbituric acid reactive substances, an index of lipid peroxidation, was increased in animals fed both fat-rich diets. This was accompanied by an increase in arachidonic acid content in these cells. Results presented suggest that lipid peroxidation in neutrophils from animals fed fat-rich diets may be associated with a consumption of H2O2 yielding more reactive oxygen-derived species such as the hydroxyl radical.

Antioxidant activity of cinnamon (Cinnamomum Zeylanicum, Breyne) extracts.

JUSTIFICATION: Lipid oxidation is one of the major changes that can occur during processing, distribution, storage and final preparation of foods. The oxidation could be prevented by adding synthetic or natural antioxidants in spite of safety of synthetic ones has been questioned. This situation promotes increasing demand for food additives of natural origin. OBJECTIVE: The objective of this study was to evaluate the antioxidant activity of cinnamon extracts. METHODS: Cinnamon samples were obtained at local market, milled (32 mesh sieve) and submitted to sequential extraction using as solvents: ether, methanol and water. The antioxidant activity in the extracts was measured by the b-carotene/linoleic acid system, at 50 degrees C and absorbances reading at 470 nm every 15 min intervals for 120 min. Two controls were used in this determination: one with synthetic antioxidant (BHT, 100 ppm) and other without antioxidant. The water extract was fraccionated using silica Gel 60 and 60G and through chromatographic processes: thin layer, (T.L.C.) and column, using BAW as mobile phase and ethylacetate, petroleum ether, methanol and water as eluent, respectively. RESULTS: The etheric (0.69 mg), methanolic (0.88 mg) and aqueous (0.44 mg) cinnamon extracts, inhibited the oxidative process in 68%; 95.5% and 87.5% respectively. The BHT control inhibited 80% oxidation. The spray reagents (1) beta-carotene/linoleic acid and (2) Fe Cl3/K3 Fe (CN)4 1% sol, showed spots in T.L.C. with antioxidant activity (1) and blue color (2), indicating the presence of phenolic compounds with Rf values of 0.50. Five fractions were obtained by column partition with antioxidant activity and the presence of phenolic compounds. SIGNIFICANCE: These results suggest that the cinnamon extracts can be used as food antioxidant together with the improvement of food palatability. Further studies are in processing of analysing the sinergic association of extracts with synthetic antioxidant and to identify compounds with antioxidant activity in cinnamon extracts.

Changes in the activities of antioxidant enzymes of the lymphoid organs of 21-day pregnant rats due to administration of fish oil by gavage.

1. The effect of fish oil administration by gavage (0.4% body weight) on activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px) and on content of thiobarbituric acid reactive substances (TBARs) of the lymphoid organs [thymus, spleen and mesenteric lymph nodes (MLN)] and liver was investigated in 21-day pregnant rats. The results were compared with those obtained by administration of soybean oil, cocoa butter and coconut oil. 2. Oil administration did not have any significant effect on antioxidant enzyme activities of the liver, whereas marked changes were found in the lymphoid organs. The MLN presented the most pronounced changes: SOD and catalase activities were increased by the four oils; GSH-Px activity was raised by soybean and fish oils; coconut oil reduced the activity of the three antioxidant enzymes in this organ. 3. Fish oil given by gavage does affect the antioxidant capacity of the lymphoid organs; however, similar effect was also observed for cocoa butter and soybean oil. These changes in the antioxidant enzyme activities were able to prevent the lipid peroxidation process in the lymphoid organs.

Composition of fatty acids in the liver and lymphoid organs of rats fed fatty acid-rich diets.

The composition of the fatty acids in the thymus, spleen and mesenteric lymph nodes was determined in rats fed polyunsaturated (UFC) or saturated (SFC) fatty acid-rich chow during 6 weeks or 14 months. The results indicated that the lipid composition of fatty acids in these tissues was modified by the type of fat given in the diets. Interestingly, the liver did not show any dietary induced change in the composition of fatty acids. The unsaturation index was raised in the lymphoid organs by UFC either after 6 weeks or 14 months. The ageing process itself increased the degree of unsaturation of fatty acids only in the spleen of the 3 groups. A high degree of unsaturation of fatty acids in the tissues may favour the occurrence of lipid peroxidation. It was noteworthy that a linoleic acid-rich diet (UFC) did not change the content of arachidonic acid in the tissues and so would therefore be unlikely to affect eicosanoid synthesis. As shown by previous studies, these fat-rich diets caused marked changes in the key enzyme activities of glucose and glutamine metabolism in the lymphoid organs, by as yet unknown mechanisms. The results reported here suggest that the effect of fat-rich diets on intermediary metabolism does not occur through eicosanoid synthesis and may be a consequence of the lipid peroxidative process or even alterations in the transcription of the enzymes of glycolysis and glutaminolysis.

[Antinutritional effect of phytohemagglutinins of Phaseolus vulgaris L]. / Ação anti-nutricional das fito-hemaglutininas de Phaseolus vulgaris,L.

The antinutritional effect caused by the ingestion of lectins from two Brazilian varieties of beans: Rico 23 and Jalo, was studied in rats. The two varieties were selected in a previous screening of toxicity in rats: one of them (Jalo) was lethal, and the other (Rico 23) was not, when injected intra-peritoneally. Different amounts of each one of the lectins were added to casein experimental diets and fed to rats. The amount of protein (casein) also varied from 5% to 20%. The addition to the diet of 1% lectins from the Jalo variety caused a growth depression, as well as a decrease in food efficiency ratio and serum glucose; also, it reduced the maltase and invertase activity of the intestinal mucosa. All these effects appeared when the protein contents in the rations were 5% or 10%. At the 20% level only a depression of the maltase activity was observed. Similar effects were shown by the lectins of the Rico 23 variety, but only when added in a higher (5%) percentage to the diet. The phosphatase and protease activity were not changed by any of the lectins. The inhibitor activity that occurred in vivo was not detected in vitro.